Process for preparing synthetic oils



manta May 940 UNITED STATES- PATENT orrics 212.1,? PROCESS FORPBEPABINGSYN'IH ETIG OILS James A. Franceway, Jr., late of Madisonvllle,Ky'., by James A.- My, 8n, administrator, Madisonvillc, Ky., and GarlandH. B. Davls, Elisa Standard oil Development Company, a corporation ofDelaware No Drawing. Application August 1, 1036, Se-

No. 98,880. In Canada December 6 Claims. (01. sci-'31) ability and thepurity at which they maybe ob- The present invention relates to theproduction of valuable lubricating oils, especially oils of low pourpoint and to methods for producing such products. Our invention willbe-fully understood from the following description of the products andtheir method-of manufacture:

Lubricating oils obtained from petroleum and especially the higher grade,lubricating'oils contain waxy constituents and in consequence thereofare characterized byhigh pour points,

that is to say, they become solid at relatively elevated temperatures,for example 30 or 40 F.

or even 50 or 75- F.,"depend ing on theamount of wax present. It is thepractice of refiners to remove a part or the whole of the wax so as tocause the oil to remain liquid to considerably lower temperatures, forexample to 10 1?. or even to 0 or lower, but this is an expensiveoperation and besides the wax is a desirable addition agent to the oilso that it is preferred not to. re-

- move it.

We. have discovered a class'of substances which when added tohydrocarbon oils improve their properties and when added to wax-comproperties of the oil; .The polymers of a particular type produced in aspecial manner from certain raw materials form the basis of the presentinvention.

The raw materials .are contained in the general class of organicmaterials which have relatively long straight hydrocarbon chains of, forexample, 10 or 12 carbon atoms or more. They may be hydrocarbons and ofthese the hydrocarbons contained in paraflln wax are desirable sincethey are characterized by substantially straight chains. The normallyliquid oils con-' taining more than 10. or 12 carbon atoms are sometimescharacterized by a marked branchy and/or cyclic structure and if so areundesirable for the present purposes.

It is not, however, necessary that the chains be fully saturated.Parrafiln waxes are, indeed, the most satisfactory and they aregenerally fully saturated, but oleflns of more than 10 carbon atomsarranged in a relatively long straight chain are equally. desirable. Thewaxes are most desirable because of their cheapness, availtainedHydrocarbons are not the only source of these desirable polymers and, infact, they may be produced from any compounds selected from the class of.the alcohols; esters, ethers, acids, ketones and the like which containhydrocarbon groups of at least 10 carbon atoms in substantially straightchains. For example, stearic acid or its esters such as the methyLethylor propyl stearates or oleic acid and its esters may be used; thealcohols above decyl, the corresponding aldehydes. and ethers of suchalcohols and related substances such as the ketones. are also available.While we prefer the naturally occurring acids or esters because of theircheapness, ma-

terials produced synthetically or, which may be mixtures of manydifferent compounds, or of compounds of. the same type but of differentnumber of carbon atoms, may be used with good results. I v

The method by which the above enumerated substances are treated toproduce suitable polymers consists in the application thereto of hightensionelectric discharges. The process is carried .out in the knownmanner under reduced pressure preferably below-about 100 mm; absolutepressure but more elevated pressures about to atmospheric, say 650mm.may be used, and provision, is made for continuously maintaining thisreduced pressure. An alternating current of cycles per second, forexample,

may be used but it is far more desirable to have greater frequencies,say 10,000, 15,000 oreven much higher. High voltages are also necessary,say 10,000 to 15,000 or higher, depending on the him of oil throughwhich the current is topass.

Any suitable apparatus as indicated above can be used for our purpose;and many types are well known. The temperature of the material should besufficient to keep it in a fluid state and it may be caused to flow in athin illm over the elec- I trodes or, to splash, foam or squirt overthem in such a way as to subject the oil in thin fllms to the action ofthe high tension discharge.

The electrodes may be placed in parallel, or in.

the form of plateswhich may be alternately dipped into andwithdrawn froma bath of the material, or, they may be in the form of concentricallyplaced tubes or drums arranged in a horizontal direction and rockedabout the horizontal axis through say to degrees or slowly rotated andin this way theoily material which may occupy something less thanone-half of the annular space between the electrodes is washed up overthe inner and the outer tube in such a way as to leave a film exposed tothe current. If desired, a small amount of gas, for instance nitrogen orhydrogen may be bubbled through the material undergoing treatmentcausing it to splash or foam. If desired, concentric electrodes may beused and rapidly rotated so as to cause the film of oil to form on theouter electrode where it is thrown by centrifugal force.

In small scale equipment it has been found desirable to continuously addheat to the material either by jacketing the vessel or by withdrawing aportion thereof, heating ityand returning it to the vessel so as tomaintain the wax or other solid material in a freely flowing liquidstate. If the oil is naturally liquid ordinary temperatures arepermissible, but. even in.

that case slightly elevated temperatures from, say to 500 F. or more,are desirable to keep the polymer in a state of reduced viscosity. Inlarger scale equipment where radiation losses are necessarily lower,less heat is required but it is ordinarily desirable in any case toprovide thermostatic jackets so as to keep the conditions substantiallythe same during the treatment.

The polymers which we desire to form have molecular weights well inexcess of 600 and substances as high as 1000 to 2000 and perhaps higherhave been found in the product. The lower polymers apparently do notpossess the desired pour depressing properties but it is extremelydimcult to separate fractions closely and to state with exactitude atjust what point this action begins. It may be stated, however, thatunpolymerized fractions of the original material, for example of paramnwax may be removed from the heavier polymers by distillation and thatthe vaporized material generally possesses no pour inhibiting propertiesor, in any case, it is very weak and that the bottoms or residueconcentrates the valuable or active material. The lighter fractions maybe returned for retreatment in the same or in a successive treatment.The distillation should be conducted with fire and steam or with vacuum,and care should be taken to remove the lighter fractions without anysubstantial cracking of the residue.

While the parafiinic materia by which we mean material containingrelatively long hydrocarbon chains, whether the compound be ahydrocarbon or whether containing oxygen, may

be used alone, it is permissible to add thereto a substance of a cyclicstructure such as benzol or naphthalene, their hydrogenated or alkylatedderivatives such as toluol, xylol and ethyl naphthalene. Hydroxylatedaromatics such as the phenols and naphthols may be used for this purposeas well as the nitrated aromatics or the amino derivatives of the typeof aniline, naphthylamine and the like. Even cyclic terpenes may beused. These materials are added in proportion of, say 10 to 14 or 20% ofthe parafiinic material and the condensation takes place insubstantially the same manner as indicated above,

but it is clear that the aromatic or cyclic mateterial is used the pourinhibiting efiect tends to diminish so that there is a decided optimumfor pour depressing. The actual amount to be used, of course, alsodepends on the concentration of the active substance in the oilypolymers. ()1- dinarily, if a good grade of polymer is produced 1% issufficient, but in some instances as little as .1 to .5% may besuflicient, and in other cases 2 to 5% may be required. It is desirable,as indicated above, to concentrate the inhibitor to 'some extent andthis is preferably done by distilling off the lower readily distillablefractions, for example, by vacuum distillation or by other suitablemeans. Where the agent is well concentrated the pour inhibiting effectmay be obtained without substantial increase in viscosity.

As an example of the operation of the present process a good grade ofparaflln wax having a melting point of 122 F. is subjected to analternating current of 60 cycles, 13,000 volts, for a period of 150hours. Temperature was carefully controlled at about F. and a pressureof 15 mm. was maintained by means of a vacuum pump. The treating vesselconsisted of a horizontally placed, jacketed tube of glass. Concentrictherein is placed a small aluminum tube fitted with holes and incommunication with the vacuum pump. The two tubes are carefullyinsulated from each other, and the melted paraffin wax is placed in theglass tube so as to just reach the level of the inner aluminum tube.These tubes are then rocked back and forth slowly on the central axisthrough an arc of about 130 degrees. The outer glass tube comprises oneof the electrodes while the aluminum tube comprises the other.

After about hours the reaction product is removed and it is topped undervacuum to remove the unchanged wax or, at least the greaterportion-thereof, together with lower polymers. The residual liquidcomprising 53% of the original wax is an oily material with thefollowing inspection:

Gravity 31.8 A. P. I.

Viscosity 3800 seconds Saybolt at 100 F. Viscosity 349 seconds Sayboltat 210 F. Flash 600 F.

Pour 70 F. Color 1 Robinson Carbon '.65%

When this material is added in concentration of 1% to an oil of about 50seconds Saybolt viscosity at 210 F. and having the normal pour point of30 F., it is observed that the oil will pour at temperatures down to 5F. There is no substantial change in the other properties of the oilexcept for a slight increase in viscosity.

In another experiment the paraffin wax was treated in an ozonizer of theusual form for 48 hours. The temperature was slightly above the meltingpoint of the wax and a pressure of about 100 mm. was maintained. Anelectric current alternating at a rate of 2,000 cycles per second wasused and the potential difference between the two electrodes was about10,000 volts. When the reaction product was withdrawn it was found thatabout 30% of the wax was .unreacted and could be removed from the heavyoil by distillation. The remaining product had a viscosity of 1500seconds Saybolt at 210 F. and when added in the proportion of 1% to theoil of the type used in Example 1 with a normal pour point of 35 F., itwas found to be depressed to -l5 F.

While it is preferred to electrically treat wax which has been separatedfrom an oil, the wax can be polymerized while dissolved in a suitableoil stock such as a lubricating oil or a hydrogenated lubricating oil.The oil in such case ispolymerized to some extent as will be appreciatedand the product although rich in wax has alow pour point due to thepresence of the inhibitor produced in situ. This product can be used asan inhibitor and added to other oils such as natural waxy oils or tohydrogenated or synthetic oils, or may be used as a lubricant as such.

This application is a continuation-in-part of application Serial No.623,814, filed July 21, 1932.

Our invention is not to belimited by any theory of the mechanism ofelectrical condensation, nor

'of pour reduction, -but only to the following claims in which we wishto claim all novelty inherent in the invention.

We claim: I

1. Process for preparing improved polymerization and condensationproducts of high molecular weight, soluble in lubricating oils andhaving the characteristic of lowering the pour point of waxy lubricatingoils when added thereto in small amounts, comprising subjecting amixture consisting essentially of parafline wax and about to 20% of anaromatic compound, in liquid phase, to an electric glow discharge of anintensity and for a period sufficient to effect substantialcopolymerization of the parafllne wax and the aromatic compound.

2. Process according to claim 1 in which the said mixture contains about10 to 20% of naphthalene.

3. Process according to claim 1 in which the said mixture contains about10 to 20% of a phenol. 4. Process according to claim 1, in which thesaid aromatic compound comprises an amine.

5. Process for preparing improved polymerization and condensationproducts of high molecular weight, soluble in lubricating oils, andhaving the characteristic of improving lubricating oils when addedthereto in small amounts, comprising subjecting a mixture consistingessentially of a saturated aliphatic compound having at least 10 carbonatoms in a straight chain andof a hydroxy aromatic compound admixed in aproportion of at least about 10% of said saturated aliphatic compound,in liquid phase, to a silent electric discharge of an intensity and fora period sufficient to effect substantial copolymerization of thesaturated aliphatic compound andth hydroxy aromatic compound.

. 6. Process for electrically polymerizing an aromatic compound to aproduct of high molecular 7 weight and soluble in lubricating oils whichcom- I prises subjecting the aromatic compound admixed with parafiinichydrocarbons containing at least 10 carbon atoms per molecule the saidmixture containing the said aromatic compound in a proportion of atleast about 10% of said paraffinic hydrocarbons, in liquid phase, tosilent electric discharges of an intensity and for a period suflicientto effect substantial copolymerization of aromatic and paraflinichydrocarbon molecules.

JAMES A. FRANCEWAY, Sic,

Administrator of the Estate of Jamet a. France-

